Electrochemistry Application — Understanding the mechanism of high capacitance in nickel hexaaminobenzene-based conductive metal-organic frameworks in aqueous electrolytes

6 measurement groups · 19 results

Reported values remain attached to the sample, method, conditions, extraction quality and source location that produced them.

Cyclic voltammetry in a three-electrode PFA Swagelok cell

Voltammetry

free-standing NiHAB composite electrode · Electrode

Free-standing NiHAB electrode on glassy carbon working electrode; overcapacitive activated carbon counter electrode; leakless Ag/AgCl reference calibrated to Ag/AgCl in 1 M KCl; 1 M aqueous KOH; 1 mV/s; typical potential range -0.75 to -0.25 V vs Ag/AgCl.

Temperature: 298
Atmosphere: aqueous electrolyte, ambient
Geometry: three-electrode cell
Context: Composite electrode containing pristine NiHAB framework.
Measurement source: 15921, 15923 · Results and Discussion; Methods, Electrochemical Measurements · Figure 1a

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Specific gravimetric capacitance in basic KOH electrolyteMarked as a best value within this paper	about 400 F/g	—	—	Text Approximate	15921 · Results and Discussion · Figure 1a
Measured charge capacity used for electron-count estimate	200 C/g measured herein	—	—	Calculated From Reported Approximate	15921 · Results and Discussion
Voltage range used for capacity calculation	0.5 V	—	—	Text Exact Reported	15921 · Results and Discussion
Experimental electron uptake per NiHAB unit	about 1 e- per NiHAB unit	—	—	Calculated From Reported Approximate	15921 · Results and Discussion

Cyclic voltammetry with potassium salts of different anions

Voltammetry

free-standing NiHAB composite electrode · Electrode

1 M KOH, 1 M KCHOO, 1 M KBr, and 1 M KF at 1 mV/s.

Temperature: 298
Atmosphere: aqueous electrolyte
Geometry: three-electrode cell
Context: Composite electrode containing pristine NiHAB framework.
Measurement source: 15922-15923 · Effect of the pH and Anion and Cation Identity · Figure 3a

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
KOH electrolyte redox features	signature redox features present in KOH	—	—	Qualitative Qualitative	15922-15923 · Effect of the pH and Anion and Cation Identity · Figure 3a
KF/KBr/KCHOO electrolyte CV shape	rectangular-shaped CVs when using KF, KBr, and KCHOO electrolytes	—	—	Qualitative Qualitative	15922-15923 · Effect of the pH and Anion and Cation Identity · Figure 3a

Cyclic voltammetry and capacitance-versus-scan-rate comparison across hydroxide electrolytes

Voltammetry

free-standing NiHAB composite electrode · Electrode

0.5 M LiOH, NaOH, KOH, TBAOH, and THAOH; 1 mV/s CVs plus capacitance from 1 to 100 mV/s.

Temperature: 298
Atmosphere: aqueous hydroxide electrolytes
Geometry: three-electrode cell
Context: Composite electrode containing pristine NiHAB framework.
Measurement source: 15922 · Surface vs Bulk Pseudocapacitance in NiHAB · Figure 2b, Figure 2c

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Tetrahexylammonium cation diameter used for comparison	~12 A	—	—	Text Approximate	15922 · Surface vs Bulk Pseudocapacitance in NiHAB · Figure 2a
Approximate capacitance range across hydroxide cations at 100 mV/s	about 65-150 F/g at 100 mV/s	—	visual estimate from Figure 2c	Visual Estimate Range	15922 · Surface vs Bulk Pseudocapacitance in NiHAB · Figure 2c
Approximate capacitance range across hydroxide cations at low scan rate	about 330-410 F/g near 0.2-1 mV/s	—	visual estimate from Figure 2c	Visual Estimate Range	15922 · Surface vs Bulk Pseudocapacitance in NiHAB · Figure 2c
Effect of cation identity on stored charge	only modest differences over the series of cations studied	—	—	Qualitative Qualitative	15922 · Surface vs Bulk Pseudocapacitance in NiHAB · Figure 2b, Figure 2c
Effective NiHAB pore size used for cation-size comparison	7.4 A pore	—	—	Text Approximate	15922 · Surface vs Bulk Pseudocapacitance in NiHAB · Figure 2a
Lithium cation diameter used for comparison	~0.9 A	—	—	Text Approximate	15922 · Surface vs Bulk Pseudocapacitance in NiHAB · Figure 2a
Pore dimension labelled in schematic	13.11 A	—	read from rendered figure label	Figure Axis Approximate	15922 · Surface vs Bulk Pseudocapacitance in NiHAB · Figure 2a

Cyclic voltammetry in hydroxyl-free organic base electrolytes

Voltammetry

free-standing NiHAB composite electrode · Electrode

1 M lithium isopropoxide in THF and sodium ethoxide in ethanol; 0.2 mV/s; Ag/AgCl wire reference.

Temperature: 298
Atmosphere: nonaqueous electrolyte
Geometry: three-electrode electrochemical cell
Context: Composite electrode containing pristine NiHAB framework.
Measurement source: S6 · Supporting Information · Figure S6

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Approximate capacitance peak in organic base electrolytes	about 400-430 F/g peak capacitance	—	visual estimate from Figure S6	Visual Estimate Range	S6 · Supporting Information · Figure S6
Redox behaviour in hydroxyl-free organic base electrolyte	same characteristic profile was reproduced	—	—	Qualitative Qualitative	15922 · Effect of the pH and Anion and Cation Identity · Figure S6

Cyclic voltammetry in sodium phosphate buffered solutions with varied pH

Voltammetry

free-standing NiHAB composite electrode · Electrode

Sodium phosphate buffered electrolytes, pH 7 to 14; 1 mV/s; cation and anion held constant.

Temperature: 298
Atmosphere: aqueous buffered electrolyte
Geometry: three-electrode cell
Context: Composite electrode containing pristine NiHAB framework.
Measurement source: 15922-15923 · Effect of the pH and Anion and Cation Identity · Figure 3b

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Approximate upper CV capacitance feature at pH 14	about 700 F/g at the positive peak/plateau	—	visual estimate from Figure 3b	Visual Estimate Uncertain	15923 · Effect of the pH and Anion and Cation Identity · Figure 3b
Approximate pH 7 rectangular CV capacitance level	about 100-150 F/g in neutral pH rectangular CV	—	visual estimate from Figure 3b	Visual Estimate Range	15923 · Effect of the pH and Anion and Cation Identity · Figure 3b
pH dependence of electrochemical response	pronounced redox features evolve to nearly rectangular-shaped CVs from basic to neutral pH	—	—	Qualitative Qualitative	15922-15923 · Effect of the pH and Anion and Cation Identity · Figure 3b

Log peak current versus log scan rate kinetic analysis

free-standing NiHAB composite electrode · Electrode

NiHAB MOF in electrolytes with pH 14, 13.4, 12, and 7; slope b compared with b = 1 capacitive and b = 0.5 diffusion-limited criteria.

Temperature: 298
Atmosphere: aqueous electrolyte
Geometry: three-electrode cell
Context: Composite electrode containing pristine NiHAB framework.
Measurement source: S7 · Supporting Information · Figure S8

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Kinetic slope b for peak current versus scan rate	b = 1 for pH 14, 13.4, 12, and 7 guide/fits	—	read from Figure S8 labels; individual fitted slopes not tabulated	Figure Axis Rounded Reported	S7 · Supporting Information · Figure S8